Traction mechanism



April 4, 1939. e. MAXON. JR

TRACTION MECHANISM Filed Nov. 22, 1937 3 Sheets-Sheet 1 INVENTOR. 2 /01444 ATTORNEY.

April 4, 1939.. G. MAXON. JR

TRACTION MECHANISM 3 Sheets-Shet 2 Filed NOV. 22, 1937 INVENT OR. BY K16 Y 0. '1 Mi ATTORNEY.

April 4, 1939. MAXON JR 2,152,654

TRACTION MECHANISM Filed Nov 22, 1937 s Sheets-Sheet 5 INVENTOR.

ATTORNEY.

Patented Apr. 4, 1939 UNITED STTES PATENT OFFICE 13 Claims.

The invention relates to traction mechanism for walking tractors.

One of the main objects of the present invention is to provide atraction mechanism having great stability and at the same time less'tail clearance than those of the prior art. According to the presentinvention, the traction mechanism includes a hollow body or foundationunit and a foot working within the hollow of said unit and cooperatingtherewith to advance the unit in one direction. A hollow body has theadvantage of being more stable than a solid body under workingconditions in machines in which walking mechanism is usually used, andit may be increased in size without changing any other part of themechanism. As the body determines the outside dimensions of myapparatus, less tail clearance is necessary as compared to the usualwalking tractors, and as a consequence my traction mechanism may be usedas a shovel or be convertible for shovel, drag-line, or ditcherequipment. As only one foot is used in conjunctiton with the body, thetraction mechanism may be made lighter and at less expense than theusual walking type tractors. Furthermore, the arrangement has theadvantage of locating the element used for travel more centrally thanthe working foundation so that the inertia of swinging is less thanexteriorly disposed travel elements.

A further object of the invention is to provide a walking mechanism inwhich a vertically extensible element, working through a bell crank, canlift or partially relieve the weight of the machine on its foundation,and at the same time transmit a horizontal force sufiicient to move orslide the foundation on the surface upon which it rests.

A further object OI the invention is to provide a walking mechanism inwhich the return stroke takes place much more quickly than the workingstroke.

A further object of the invention is to provide an adjustable connectionbetween parts of the walking mechanism whereby the relationship betweenvertical and horizontal forces can be modified for hill climbing or evenvertical jacking.

A further object of the invention is to provide a walking mechanismwhose direction of movement may be reversed if desired.

A further object of the invention is to provide extensible hydraulicallyoperated elements between the foundation and the traveling element.

The invention further consists in the several features hereinafter setforth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a vertical sectional View through an apparatus embodying theinvention, parts being broken away;

Fig. 2 is a plan view of the apparatus, oil tank being omitted;

Fig. 3 is a detailed elevation view through the hydraulic operatingmechanism, parts being broken away and parts being shown in section;

Fig. 41s a detailed view of one of the hydraulic circuits, the valvebeing shown in section.

Referring to the drawings, the apparatus comprises a hollow foundationor body unit 6, a foot or travel member 7 working within the hollow ofsaid unit, and means for alternately raising and shifting these partsrelative to each other to move the apparatus in one direction.

The foundation or body unit 6 preferably has a base member 8 upon whicha roller-supported turntable 9 is mounted, said turntable forming therotating base of the machine upon which a boom ID or other equipment forexcavating or other machines may be mounted.

The travel member I is pivotally connected at each of its opposite endsto one of the arms of bell crank levers H. Each of these levers isoperatively connected by a link IE to the base 9. The other arm of eachlever l I has an extensible operating'connection with the frame E3 ofthe base 9. As the member 7 is carried by the base, it will revolve withsaid base, and the levers II are so positionedas to mountsaid member Ifor movement toward or away from the boom or the front end oftheapparatus.

The extensible operating'connection between each lever H and the framel3 comprises a hydraulic cylinder l4 pivotally connected at its lowerend M to said lever Hand a piston I 5 working in said cylinder andhavingits rod [6 pivotally' connected at its upper end to a shaft l Icarried by the frame l3. The piston and its rod i6 is preferablyprovided with a duct l8 into which hydraulic fluid is introduced from apipe 49 to move the cylinder I l outwardly while hydraulic fluidintroduced into the cylinder from a pipe 20 acts to move the cylinderupwardly relative to the piston. These connections are alternatelyestablished through a control valve hereinafter described.

The pipe 19 for each cylinder connects with one side of a valve housing2! while the pipe 26 conn'ects with the opposite side of said housing. Apressure supply pipe 22 leads from the pump 23 to the housing, and afluid tank 2% has a pipe. 2 5 provided with a branch pipe 25 connectedwith the inlet of the pump 23 and a branch pipe 26 connected with thehousing 2!. A plug valve 21 works in a bore 28 in the housing and has athrough passage 29 connecting the pressure pipe 22 with the return 26for no delivery, a groove 36 for connecting the pipe I 9 either with thepipe 26 or the pipe 22 and a groove 3| for connecting the pipe 20 eitherwith the pipe 22 or the pipe 26.

The pipes 20 and 24 are flexible pipes to permit the movement of thepistons l5 and cylinders I4. When the valve 21 is turned to connectgroove 3| with pipes 20 and 22, the groove 36 connects pipe IS with pipe26, and when the valve is turned to connect groove 3| with pipes 20 and26, the groove 36 connects the pipe IS with the pipe 22.

The valve 21 is provided with a handle 32 for manual or power operation,and both the pump 23 and valve are mounted on a transverse frame 33which is. secured at its ends to the rods l6. The pump may be driven inany suitable manner and is shown as provided with a sprocket wheel 23connected by a chain 35 with a sprocket 36 on one of the engine drivenshafts 31 of the machine through any suitable clutch 31', the chainbeing maintained at the proper tension by an idler sprocket 38 mountedon an arm 36 pivotally supported at 40 on the frame of the machine andurged outwardly by a spring 4|.

With this construction when hydraulic pressure fluid is introducedthrough the piston duct I8 into the lower end of the cylinder I 4 andthe fluid in back of the'piston exhausted through the pipe. 26, thecylinder is forced downwardly while the piston l5 tends to moveupwardly. Under this action of the extensible operating means the partsmove from the full line position shown in Fig, l to a position along theaxis of the dotted line there shown, and the foot I moves from itsraised position to its dotted line lifting position. The foot actuallymakes contact with the ground before the levers ll swing to the dottedline position, and as soon as contact is made, the levers H in swingingexert a backward pull on the links l2 and hence on the foundation 6which is then being raised through the action of the pis- 7 tons l4, andas a consequence the foundation is pulled back to the full line positionshown in Fig. 1. One end or the other of the foundation may be raisedfirst depending upon the location of the center of gravity of saidfoundation relative to said foot member. Then as the fluid is exhaustedthrough the duct l8 and the pipe I 9 from in front of the piston M, thepressure fluid is introduced through the pipe 26 in the cylinder behindthe piston, and the cylinder with its parts is then moved upwardly whilethe piston l5 moves downwardly to the full line position shown inFig. 1. During this movement the foot I, lever II, and links l2 movefrom their dotted line position to their full line position, and theapparatus is then ready to take another step backward. As the area ofthe cylinder behind the piston is less than that in front, the backwardstroke of the lever will take place in less time than the forward strokefor the same speed of the pump 23, and in the present instance thereturn stroke of the extensible means takes place in half the time ofthe forward or lifting stroke. With this form of operating connectionbetween the foundation 6 and the foot member I, it is only necessary toraise the foundation 6 to relieve the weight thereof so that thefoundation is not raised much off the ground with the result that whenit comes to rest, there is no appreciable shock or jar, and as soonasthe foot contacts the ground, there is a tendency to swing the bellcranks I I, which tendency increases as the lifting force increases, andwhen this lifting force has increased sufliciently, the machine willwalk.

With the above arrangement the foot member I is in compression under theloads imposed on it and may, therefore, be made relatively light whilethe bell crank levers ll take any bending or torque strains.

The base 8 of the foundation is preferably of hollow cylindrical form,andthe foot member I has converging sides 42 curved to substantially thesame curvature as the inner wall of said base 8.

To adjust the amount of lift, spaced holes 43 may be provided in thebase 9 to change the position of the outer end of each link 12.

The apparatus has been arranged for the machine to walk backward.However, if the links are arranged for connection with the base throughholes 43' at the opposite side from the holes 43 and the foot, levers,and extensible operating connections reversed, the machine will thenwalk forward under the action of the relative movement between pistonsand the cylinders as in the first described construction.

It is to be noted that the hollow foundation 6 offers greater overallstability during the working of excavating machines, such as shovels,draglines, and cranes, than a solid base of equal area or in someinstances of equal outside diameter. wholly disposed within the confinesof the found- Furthermore, since the foot member is ation, less tailclearance for the parts. on the rotating base is necessary so that thepresent arrangement can be used for shovel type excavators and ispractical in smaller sizes because.

of its ability to take shovel, dragline, or ditcher equipment.

While the operating means is shown as hydraulically operated, theinvention is not to be limited thereto, but other forms of operatingmeans may be used if they come within the scope of the invention asdefined by the appended claims.

I desire it to be understood that this invention is not to be limited toany particular form or arrangement of parts except in so far as suchlimitations are included in the claims.

. What I claim as my invention is:

1. Apparatus of the type described comprising a hollow main framedetermining substantially the outside dimensions of the propellingmechanism of the apparatus, a foot member working within the hollow ofsaid main frame, each of said parts adapted to carry the other, andmeans connecting said frame and foot member for alternately raising saidparts during translatory movement thereof in one direction. 7

2. Apparatus of the type described comp-rising a hollow main foundationunit determining substantially the outside dimensions of the propellingmechanism of the apparatus, a foot member working within the hollow ofsaid unit, each of said parts adapted to carry the other, and means forconnecting said foot member to said unit for raising and translatorymovements of said foundation unit.

3. Apparatus of the'type described comprising a hollow main foundationunit determining sub: stantially the outside dimension of the propellingmechanism of the apparatus. a foot member working within the hollow ofsaid unit, each of said parts adapted to carry the other, a leveroperatively connected to said unit and to said foot member, and meansfor swinging said lever to raise and lower said foot member and exert alifting and pulling action on said unit.

4. Apparatus of the type described comprising a hollow main foundationunit determining substantially the outside dimensions of the propellingmechanism of the apparatus, a foot member working within the hollow ofsaid unit, each of said parts adapted to carry the other, a leveroperatively connected to said unit and to said foot member, andextensible and contractible means connecting said lever with said unitfor swinging said lever to raise and lower said foot member and exert alifting and pulling action on said unit.

5. Apparatus of the type described comprising a hollow main foundationunit determining substantially the outside dimensions of the propellingmechanism of the apparatus and having a rotating base, a foot memberworking within the hollow of said unit, said unit and said foot membereach adapted to carry the other, and means for connecting said footmember to said rotating base for raising and translatory movements ofsaid foundation unit.

6. Apparatus of the type described comprising a hollow main foundationunit determining substantially the outside dimensions of the propellingmechanism of the apparatus and having a rotating base, a foot memberworking within the hollow of said unit, said unit and said foot membereach adapted to carry the other, a lever operatively connected to saidrotating base and to said foot member, and means connecting said leverat another point to said rotating base for swinging said lever to raiseand lower said foot member and exert a lifting and pulling action onsaid unit.

'7. Apparatus of the type described comprising a hollow main foundationunit determining substantially the outside dimensions of the propellingmechanism of the apparatus, a foot member working within the hollow ofsaid unit, each of said parts adapted to carry the other, a leveroperatively connected to said unit and to said foot member, andhydraulically operated means connecting said lever with said unit forswinging said lever to raise and lower said foot member and exert alifting and pulling action on said unit.

8. Apparatus of the type described comprising a hollow main foundationunit determining substantially the outside dimensions of the propellingmechanism of the apparatus, a foot member working within the hollow ofsaid unit, each of said parts adapted to carry the other, a leveroperatively connected to said unit and to said foot member, a hydrauliccylinder and a piston working in said cylinder, one of said last namedparts being connected to said lever and the other to said unit, andmeans for introducing hydraulic fluid under pressure alternately onopposite sides of said piston to swing said lever to raise and lowersaid foot member and exert a lifting and pulling action on said unit.

9. Apparatus of the type described comprising a hollow foundation unit,a foot member working within said unit, each of said parts adapted tocarry the other, a lever having one end vertically adjustably connectedto said unit and an arm operatively connected to said foot member, saidlever having another arm, and means connected to said last named arm toswing said lever to raise and lower said foot member and exert a liftingand pulling action on said unit.

10L Apparatus of the type described comprising a hollow foundation unit,a foot member working within said unit, each of said parts adapted tocarry the other, a bell crank lever, a link operatively connecting onearm of said lever to said unit, operating means operatively connectingthe other arm of said lever with said unit for swinging said lever andexerting a lifting force on said unit, both arms of said lever beingconnected to said foot.

11. Apparatus of the type described comprising a hollow main foundationunit, a foot member working within said unit, each of said parts adaptedto carry the other, a bell crank lever, a link operatively connectingone arm of said lever to said unit, extensible and contractibleoperating means operatively connecting the other arm of said lever withsaid unit for swinging said lever and exerting a lifting force on saidunit, both arms of said lever being connected to said foot.

12. Apparatus of the type described, comprising a hollow main foundationunit, a foot member working within said unit, each of said parts adaptedto carry the other, a bell crank lever operatively connected to saidfoot member and having floating connections with said unit, and meansfor moving one of said floating connections to swing said lever to exerta lifting force on said unit.

13. Apparatus of the type described, comprising a frame member, a footmember coacting with said frame member, each of said parts adapted tocarry the other, a bell crank lever operatively connected to said footmember and having floating connections with said frame member, and meansfor moving one of said floating connections to swing said lever to exerta lifting force on said frame member.

GLENWAY MAXON, JR.

,,,,,,,,,,,, d l m fl fi. im m p CERTIFICATE OF CORRECTION Patent No.2,152,65L April L 19 9.

GIENWAY MAXON, JR.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows Page 2,second column, line 71, claim5, for "dimension" read dimensions; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 23rd day of May, A. D. 1959.

. Henr Van Ar (Seal) Acting a nnnissione r i Tatent s

